Where do they get the numbers for PC1600 and PC2100?

[Amedeo602]

I know that in the DDR world PC1600 is equivalent to PC100 and 2100 is 133. The numbers double (to 200/266), then they're multiplied by 8??

I know there's a reason (they wanted a bigger number than PC800), but why did they choose 1600 and 2100? I read it somewhere, but I forget where...help

 

[UnseenMenace]

Double Data Rate SDRAM is little more than a small evolution of current SDRAM technology. DDR SDRAM is capable, like RDRAM, of transferring data on both the rising and falling edges of the clock cycle. As such, its effective bandwidth is doubled. Consider standard 100 MHz DDR SDRAM:

(100 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 1600 MB/s available bandwidth.

As the numbers illustrate, DDR SDRAM, in conjunction with a 100 MHz FSB can provide bandwidth equivalent to that of RDRAM. Of course, like standard SDRAM, DDR SDRAM can be made to operate at a 133 MHz FSB as well.

(133 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 2133 MB/s available bandwidth.

When utilized with a 133 MHz FSB, DDR SDRAM can provide greater bandwidth than RDRAM. Thus, DDR SDRAM is able to achieve equal, or even higher, bandwidth levels while maintaining SDRAM’s lower latency.

 

[David]

DDR RAM can run at the same speed as the FSB of some AMD processors. I'm not sure of the P4 FSB but I think its 400MHz. This means that 800MHz RDRAM can't really achieve its full bandwidth as there is a bottleneck in the data bus between RAM and processor

*I think this is right. If it isn't, please correct me *

 

[UnseenMenace]

DDR RAM can run at the same speed as the FSB of some AMD processors. I'm not sure of the P4 FSB but I think its 400MHz. This means that 800MHz RDRAM can't really achieve its full bandwidth as there is a bottleneck in the data bus between RAM and processor

*I think this is right. If it isn't, please correct me *

I believe that the AMD processors quoted as being DDR feature a 266 mhz FSB which is in fact a internally double pumped 133 mhz FSB. The Pentium 4 has a 100 mhz FSB which is quad pumped internally to obtain a 400 mhz FSB

 

[oc jason]

pc1600 is pc100 rated DDR, and can hadlve 1.6gb a sec bandwidth

pc2100 is pc133 rated DDR, and can handle 2.1gb a sec bandwidth

pc2400 is pc150 rated DDR, and can handle 2.4gb a sec bandwidth.

So on and so Forth

 

[rUfUnKy]

Double Data Rate SDRAM is little more than a small evolution of current SDRAM technology. DDR SDRAM is capable, like RDRAM, of transferring data on both the rising and falling edges of the clock cycle. As such, its effective bandwidth is doubled. Consider standard 100 MHz DDR SDRAM:

(100 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 1600 MB/s available bandwidth.

As the numbers illustrate, DDR SDRAM, in conjunction with a 100 MHz FSB can provide bandwidth equivalent to that of RDRAM. Of course, like standard SDRAM, DDR SDRAM can be made to operate at a 133 MHz FSB as well.

(133 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 2133 MB/s available bandwidth.

When utilized with a 133 MHz FSB, DDR SDRAM can provide greater bandwidth than RDRAM. Thus, DDR SDRAM is able to achieve equal, or even higher, bandwidth levels while maintaining SDRAM’s lower latency.

Had to read that a couple times but i gut it now ..um just don't ask me to repeate it tommorow..

 

[Amedeo602]

Double Data Rate SDRAM is little more than a small evolution of current SDRAM technology. DDR SDRAM is capable, like RDRAM, of transferring data on both the rising and falling edges of the clock cycle. As such, its effective bandwidth is doubled. Consider standard 100 MHz DDR SDRAM:

(100 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 1600 MB/s available bandwidth.

As the numbers illustrate, DDR SDRAM, in conjunction with a 100 MHz FSB can provide bandwidth equivalent to that of RDRAM. Of course, like standard SDRAM, DDR SDRAM can be made to operate at a 133 MHz FSB as well.

(133 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 2133 MB/s available bandwidth.

When utilized with a 133 MHz FSB, DDR SDRAM can provide greater bandwidth than RDRAM. Thus, DDR SDRAM is able to achieve equal, or even higher, bandwidth levels while maintaining SDRAM’s lower latency.

ahh, that's right. i knew there was a reason for it